Carbonylation catalysts

ABSTRACT

A carbonylation catalyst composition comprising a mixture of: 
     (a) (C 4  H 8  O) 4  Mg[Co(CO) 3  P(C 4  H 9 ) 3  ] 2  or (C 4  H 8  O) 4  Mg[Rh(CO) 3  P(C 4  H 9 ) 3  ] 2  and an organo iodine compound selected from the group consisting of CH 3  I, CH 2  CH 3  I, and C 6  H 5  I.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation, of appliction Ser. No. 17,717, filed Mar. 5,1979 now abandoned, which is a Division of Ser. No. 799,589, filed May23, 1977, now abandoned, which is a CIP of 166,615, filed July 27, 1971,now abandoned, which is a CIP of Ser. No. 51,669, filed July 1, 1970,now abandoned.

FIELD OF THE INVENTION

The present invention is directed to a carbonylation process for thepreparation of carboxylic acid esters wherein carbon monoxide iscontacted with at least one alcohol in the presence of a catalyst systemhaving the general formula:

    B.sub.x M[Me'(CO).sub.a (L).sub.b ].sub.2

and a cocatalyst comprising halogen containing compounds in a cocatalystto catalyst molar ratio ranging from about 1 to about 16, wherein B is aLewis base capable of coordinating with a Group IIA metal; Me is a GroupIIA metal, preferably magnesium; Me' is a transition metal selected fromthe group consisting of metals of Groups VIB, VIIB and VIII of thePeriodic Table of the Elements; L is a uni- or polydentate ligand orhydrocarbon capable of coordinating with the transition metal; x is apositive integer ranging from 1 to 4; a is a positive integer rangingfrom 1 to 5; b is an integer ranging from 0 to 4, with the proviso thatthe sum of a and b is 5 or less. A typical preferred catalyst system isrepresented by the general formula: (C₄ H₈ O)₄ Mg [Co(CO)₃ P(C₄ H₉)₃ ]₂and a cocatalyst comprising methyl iodide in cocatalyst to catalystmolar ratio of ranging from 1 to 4.

DESCRIPTION OF THE PRIOR ART

Carbonylation processes wherein alcohols, ethers, esters andhalogen-containing compounds are contacted with carbon monoxide at hightemperatures and pressures are known in the art. The catalysts whichhave been utilized in the prior art processes are generally Group VIIImetals, e.g., cobalt, nickel and iron salts which under thecarbonylation reaction conditions will be converted to carbonylcompounds.

In U.S. Pat. No. 2,650,646 there is disclosed a process forcarbonylating methanol by contacting methanol with carbon monoxide inthe presence of a nickel carbonyl compound and methyl iodide. Thispatent also indicates that the volatility of the nickel carbonyl andmethyl iodide pose a problem to the skilled artisan. For example, it isknown that catalyst loss due to volatility is a severe problem whenemploying any of the simple carbonyl derivatives of cobalt, nickel andiron.

In U.S. Pat. No. 2,710,878 a further problem in the process for theconversion of an alcohol to an organic acid in the presence of acatalyst system comprising a nickel or a cobalt salt and a halidecocatalyst is disclosed, i.e., the necessary high temperatures,pressures and acidic reaction mixtures cause extreme corrosion of theusual reactor equipment.

U.S. Pat. Nos. 2,898,366 and 2,898,367 disclose a process wherein loweraliphatic alcohols are reacted with carbon monoxide in the presence of acatalyst system comprising a nickel salt and iodine and/or hydrogeniodide at temperatures of at least 325° C. and pressures upwards of3,000 psi.

U.S. Pat. No. 3,014,962 discloses a more active catalyst system whereina chelating compound is added to the iron, cobalt and nickel saltcatalyst and halogen containing cocatalyst of the prior art processes.This catalyst system produces carboxylic acids as the major product.

U.S. Pat. Nos. 2,734,193 and 3,505,408 describe carbonylation catalystsystems wherein the nickel or cobalt is in the anion of a complex salt.These systems, although useful in the hydroformylation of olefins, arenot very active alcohol carbonylation catalysts.

The covalent nature of bonds between main group elements and transitionmetals has been well established by numerous chemical, structural, andspectroscopic investigations. Many compounds are known in which a mainGroup IVA or IIB metal is covalently bonded to a transition metal. Casesin which a transition metal is bonded to an element of main Group IIA orIIIA are, by contrast, few in number. Group IA transition metalcompounds are known but are essentially ionic and are generally notisolatable and are handled as solutions in polar solvents.

It is generally found that the covalent nature of a main Group IIIA ormain Group IVA metal bonded to a transition metal decreases as one movesfrom Group IVA to Group IIIA or ascends either respective group. Thistrend in covalent bonding is responsible for the failure of the earlynumbers of Group IIIA to form readily insoluble compounds withtransition metals (the transition metal anion is the seat of reactivityand is readily attacked by electrophiles).

Group IIA-transition metal compounds have been described in twoinstances, but in both cases hereafter noted, the proposed compositionand structure was incorrectly postulated. Von W. Hieber et al.,Zeitschrift fur anorganische und allgemeine Chemie, pp. 125-143 (March,1962) described the reaction of a dimeric manganese carbonyl complexwith magnesium amalgam in the presence of tetrahydrofuran to give thebis-tetrahydrofuran adduct of a magnesium-manganese carbonyl complex.This product is not produced under the reaction conditions described;instead the tetrakis adduct is obtained in quantitative yield.Furthermore, Hieber et al, only teach a method for preparing the complex(C₄ H₈ O)₂ Mg[Mn(CO₄)P(C₆ H₅)₃ ]₂. The stability of this complex islargely due to the stabilizing effect of the phosphine ligand P(C₆ H₅)₃.The ability of P(C₆ H₅)₃ to impart thermal stability to carbonylcomplexes is well documented in the literature.

Burlitch and Ulmer, Journal of Organometallic Chemistry, 19 pp. 21-23(1969) described the preparation of halides of magnesium transitionmetal carbonyl complexes (transition metal carbonyl Grignard reagents)by the reaction of the transition metal carbonyl halide with magnesiumin the presence of tetrahydrofuran. Burlitch and Ulmer did not isolatethese products, but inferred that they existed by further reactions ofthe unisolated complex. The applicant has found that halide derivativesof magnesium-transition metal carbonyl complexes cannot be isolated,but, instead, if formed, immediately dispropertionate to givebistransition metal derivatives of magnesium complexed with Lewis basemolecules and magnesium halide.

Group IIA-transition metal compounds would be expected to be more ionicin nature than the corresponding IIB derivatives. A balance betweencovalent and ionic bonding contributions to the hetero metal-metal bondis needed to insure reasonable solubility in organic solvents.Hydrocarbon solubility is, of course, a necessity for use of the GroupIIA-transition metal compound as a homogeneous catalyst forhydrogenation, polymerization, dimerization, carbonylation andhydroformylation reactions:

DISCOVERY OF THE INVENTION

It has been unexpectedly found that a transition metal carbonyl can bereacted with a metal chosen from Group IIA of the Periodic Table of theElements in the presence of a Lewis base, to give novel compounds,wherein the transition metal is bonded to the Group IIA. This reactionis effected, preferably, by the reaction of an amalgam of the Group IIAmetal with a dimeric transition metal carbonyl complex.

It has also been discovered that these novel compounds are effectivecatalysts for carbonylation reactions to produce acids, esters, ethersand acyl halides.

More particularly it has been discovered that these novel compoundsprovide an excellent catalyst system when used in combination 2--ahalogen containing compound as a cocatalyst to produce carboxylic acidesters from alcohols.

SUMMARY OF THE INVENTION

One aspect of the present invention is directed to an improvedcarbonylation process comprising contacting a compound of the generalformula R-X wherein R represents a hydrocarbyl radical and X representsa halogen, hydroxyl or bisulfide radical (SH) with carbon monoxide inthe presence of a novel catalyst system, said novel catalyst systemcomprising a Group IIA metal-transition metal carbonyl catalyst whereinthe transition metal is bonded to the Group IIA metal and a halogencontaining cocatalyst, preferably an iodine-containing catalyst and morepreferably an iodine containing compound selected from the groupconsisting of I₂, HI, and organo iodides such as CH₃ I, CH₃ CH₂) and C₆H₅ I. An especially preferred iodine compound is CH₃ I. Preferably Xrepresents a hydroxyl radical and thus alcohols are the preferredcarbonylation reactants.

Another aspect of the present invention is directed to an improvedcarbonylation process comprising contacting an olefinic compound and analcohol with a carbon monoxide containing gas in the presence of a novelcatalyst system, said novel catalyst system comprising a Group IIAmetal-transition metal carbonyl catalyst wherein the transition metal isbonded to the Group IIA metal and having the general formula:

    B.sub.x Me(M).sub.2

wherein B is a Lewis base; x is an integer ranging from 1 to 4; Me is aGroup IIA metal; and M is a transition metal carbonyl or substitutedtransition metal carbonyl complex.

The processes of the present invention provide an improved means forobtaining carboxylic acid esters and ethers. By use of the improvedcatalyst system of the instant invention, the following improvements arenoted:

(1) Lower temperatures and pressures may be used.

(2) Either ethers or esters may be selectively produced by varying theratio of the catalyst and cocatalyst.

(3) The catalyst system is non-volatile.

(4) The reaction mixtures are non-corrosive.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred aspect of the present invention relates to a carbonylationprocess for the preparation of carboxylic acid esters which comprisescontacting carbon monoxide with at least one alcohol at a temperature inthe range from about 100° to about 200° C. and at a carbon monoxidepartial pressure in the range from about 1000 to about 4000 psig in thepresence of a catalyst system having the general formula:

    B.sub.x Me[Me'(CO).sub.a (L).sub.b ].sub.2

and a cocatalyst comprising halogen containing compounds in a cocatalystto catalyst molar ratio ranging from about 1 to about 16, wherein B is aLewis base capable of coordinating with a Group IIA metal, Me' is atransition metal selected from the group consisting of metals of GroupsVIB, VIIB and VIII of the Periodic Table of Elements, Me is a Group IIAmetal, L is a uni- or polydentate ligand or hydrocarbon capable ofcoordinating with said transition metal; x is a positive integer rangingfrom 1 to 4; a is a positive integer ranging from 1 to 5 and b is aninteger ranging from 0 to 4, with the proviso that the sum of a and b is5 or less. The catalyst is preferably an iodine containing compoundselected from the group consisting of I₂, HI, and organo iodides such asCH₃ I, CH₃ CH₂ I and C₆ H₅ I. In especially preferred iodine compound isCH₃ I.

This process is capable of producing carboxylic acid esters in highyield and good selectivity at low temperatures and pressures. Theseadvantages are attributed to the use of the novel catalyst compoundswherein the transition metal is bonded to the Group IIA metal.

The alcohols used as the preferred starting materials in thecarbonylation process include the hydrocarbyl alcohols such as alkanolsand aralkanols which contain from 1 to about 20 carbon atoms. Preferredalcohols include methanol, ethanol, propanol, isopropanol, butanol, andmixtures thereof, methanol being particularly preferred.

In general, the carbonyl ion process of the instant invention will takeplace at a temperature of from 100° to 400° C. and at a carbon monoxidepartial pressure ranging from about 500 to about 10,000 psig, dependingon the preponderance of products desired, i.e., ethers or esters.

The alcohol reactant may be contacted with the carbon monoxidecontaining gas neat or dissolved in a solvent. Solvents which can beutilized in the process of the instant invention include benzene,toluene, tetrahydrofuran, ethyl ether, etc.

It is obvious that the carbon monoxide does not have to be added to thereaction product in pure form. It may be combined with various inertgases. For example, an especially economical source of carbon monoxide,i.e., from partial combustion or steam reforming processes, will containCO₂ and hydrogen as well as carbon monoxide. This mixture can be used inthe process of the instant invention.

The molar ratio of the catalyst system to the alcohol reactant may varyfrom 0.0001 to 0.1, preferably 0.001 to 0.1. The molar ratio ofco-catalyst to catalyst may vary from 1 to 100, preferably from 1 to 4,depending on the preponderance of product, i.e., ether or ester if onewishes to obtain as explained below.

The reaction time will be apparent to the skilled artisan and he maychoose his reaction time based on the temperatures and pressuresutilized.

The instant process is capable of being run batchwise or continuously.The process of the instant invention will usually be run in reactorsknown to the skilled artisan and includes, because of the oxygensensitivity of the catalyst system of the instant invention, provisionsfor the exclusion of oxygen. It is noted that special reactor lines arenot needed in the process of the instant invention because of therelatively low temperatures and pressures utilized and the noncorrosivenature of the catalyst.

In practicing the process of the instant invention, a hydrocarbylalkanol having from 1 to 20 carbon atoms is contacted with carbonmonoxide in the presence of the novel catalyst system at an elevatedtemperature and pressure for a time sufficient to convert at least someof the alcohol to a carbonylated product. The composition of the finalreaction product, i.e., ester or ether, is controlled by varying thereaction conditions including the cocatalyst to catalyst ratio. It hasbeen discovered that ester formation is favored by increased carbonmonoxide partial pressures and low cocatalyst to catalyst ratios,whereas ether formation is favored by relatively high ratios ofcocatalyst to catalyst, high temperatures and low carbon monoxidepressures.

For example, a carbon monoxide pressure ranging from about 500 to 1000psig favors ether formation, whereas carbon monoxide pressures rangingfrom 1000 to 4000 psig favors ester formation. A temperature rangingfrom 200 to 400° C. favors ether formation whereas temperatures rangingfrom 100° to 200° C. favors ester formation. A cocatalyst to catalystmolar ratio range of from 16 to 100 favors ether formation, whereas acocatalyst to catalyst molar ratio of from 1 to 16 favors esterformation.

It will be noted that the process of the instant invention is capable ofbeing operated at low temperatures and pressures compared to the priorart processes and therefore represents a significant advantage. Also,increased selectivity to ester (when desirable), high catalyststability, and noncorrosive reaction mixture are important improvementsof the present process over the known-in-the-art carbonylationprocesses.

The process of the instant invention is also applicable to theproduction of unsymmetrical ethers and esters. For example, a mixture ofmethanol and isopropanol when reacted under conditions to yield etherswill give the following products: dimethyl ether, diisopropyl ether andmethyl isopropyl ether. Similar results are obtained when the reactionis run under conditions so that an ester product will be dominant, i.e.,methyl acetate, isopropyl acetate, and small amounts of methylpropionate and isopropyl propionate will be produced. In general, in aprocess for producing esters, the lower alcohol will preferably form theacyl function. Of course, the reaction conditions can be adjusted sothat mixtures comprising both esters and ethers are formed at once. Theformation of unsymmetrical lower alkyl ethers is especially importantsince these products have utility as octane improvers for gasolines.

The Novel Catalyst Compounds

The novel catalyst compounds used in the carbonylation process of thepresent invention are preferably those represented by the generalformula:

    B.sub.x Me[Me'(CO).sub.a (L).sub.b ].sub.2

B is a Lewis base capable of coordinating with a Group IIA metal, suchas magnesium, through a lone pair of electrons thereby stabilizing theGroup IIA metal-transition metal complexes. The Lewis base is preferablya member selected from the group consisting of:

1. Organic nitrogen bases;

2. Ethers; and

3. Ketones. Me is a Group IIA metal, preferably magnesium; Me' is atransition metal selected from the group consisting of Groups VIB, VIIBand VIII metals (examples of the useful transition metals includemolybdenum, tungsten, cobalt, nickel, ruthenium, rhodium, palladium,osmium, iridium and platinum, cobalt being the most preferred); L is auni- or polydentate ligand capable of coordinating with the transitionmetal or a hydrocarbon residue; x is a positive integer ranging from 1to 4; a is a positive integer ranging from 1 to 5; b is an integerranging from 0 to 4, with the proviso that the sum of a and b is 5 orless.

The organic nitrogen bases (B) useful as Lewis bases to coordinate withthe Group IIA metal and selected from the group consisting of:

(a) monofunctional nitrogenous bases represented by the generalformulae: ##STR1## R--NH₂ ; and NH₃ wherein R, R' and R" are hydrocarbylradicals independently selected from the group consisting of C₁ to C₁₀alkyl, C₃ to C₁₀ cycloalkyl, C₆ to C₁₀ aryl and C₇ to C₁₀ alkaryl andaralkyl radicals;

(b) polyfunctional nitrogenous bases represented by the general formula:##STR2## wherein R" and R^(iv) are selected from the group consisting ofhydrogen and C₁ to C₁₀ hydrocarbyl radicals, R₁ is selected from thegroup consisting of hydrogen and C₁ to C₄ alkyl radicals, Z is selectedfrom the group consisting of radicals represented by the generalformulae: ##STR3## wherein R₁, R₂, R₃, R₄, R₅ and R₆ are independentlyselected from the group consisting of hydrogen and C₁ to C₄ alkylradicals and y is a positive integer ranging from 1 to 3; and

(c) Heteroring nitrogenous bases selected from the group consisting ofpiperazine, pyrrolidine, pyridine and substituted pyridines of theformula: ##STR4## wherein R₆ is a C₁ to C₁₀ hydrocarbyl and z is aninteger from 0 to 5.

Preferred examples of organic nitrogen bases which are within the abovedescription include: monofunctional nitrogenous bases:

Ammonia

Methylamine

Dimethylamine

Trimethylamine

Triethylamine

Methyl diethylamine

Pyridine

N-decyl pyridine

Aniline

Bifunctional nitrogenous bases:

2,2'-bipyridyl

1,10-phenanthroline

Ethylene diamine

tetramethylethylenediamine

1,3-propylene diamine

Tetrafunctional nitrogenous bases: ##STR5##Hexamethyltriethylenetetraamine Triethylenctetramine

The ethers useful as Lewis bases (b) to coordinate with the Group IIAmetal are selected from the group consisting of:

(a) monofunctional ethers represented by the general formula:

    R--O--R'

wherein R and R' are hydrocarbyl radicals independently selected fromthe group consisting of C₁ to C₁₀ alkyl, C₃ to C₁₀ cycloalkyl, C₆ toC₁₀, C₇ to C₁₀ alkaryl and aralkyl radicals;

(b) polyfunctional ethers represented by the general formulae: ##STR6##wherein R₁, R₂, R₃, R₄, R₅ and R₆ are independently selected from thegroup consisting of hydrogen and C₁ to C₄ alkyl radicals, R and R' arehydrocarbyl radicals independently selected from the group consisting ofC₁ to C₁₀ alkyl, C₃ to C₁₀ cycloalkyl, C₆ to C₁₀ aryl and C₇ to C₁₀alkaryl and aralkyl radicals and y is a positive integer of from 1 to 3;and

(c) cyclic ethers selected from the group consisting of tetrahydrofuranand dioxane.

Examples of mono-, bi- and tetrafunctional oxygenated ethers which cancoordinate to Group IIA metals, e.g., magnesium through a lone pair ofelectrons thereby stabilizing the Group IIA metal-transition metalcomplexes are listed below.

Monofunctional ethers

Tetrahydrofuran

Tetrahydropyran

Dioxane

Diethyl ether

Dipropyl ether

Methyl ethyl ether

Dicyclohexyl ether

Diphenyl ether

Methylphenyl ether

Difunctional ethers

CH₃ OCH₂ CH₂ OCH₃ (glyme)

CH₃ CH₂ OCH₂ CH₂ OCH₂ CH₂ (1,2-di-ethoxyethane)

C₃ H₇ OCH₂ CH₂ OCh₂ CH₃ (1-propoxy-2-ethoxyethane)

C₆ H₅ OCH₂ CH₂ OC₆ H₅ (1,2-diphenoxy-ethane)

Tetrafunctional ethers

CH₃ OCH₂ CH₂ OCH₂ CH₂ OCH₂ CH₂ OCH₃ (triglyme)

Ketones useful as Lewis bases (B) to coordinate with the Group IIA metalare represented by the general formula: ##STR7## wherein R and R' arehydrocarbyl radicals independently selected from the group consisting ofC₁ to C₁₀ alkyl, C₃ to C₁₀ cycloalkyl, C₆ to C₁₀ aryl and C₇ to C₁₀alkaryl and aralkyl radicals, R₁ and R₂ are independently selected fromthe group consisting of hydrogen and C₁ to C₄ alkyl radicals and z is aninteger of from 0 to 3.

Examples of useful ketones are listed below:

Acetone

Methyl ethyl ketone

Dicyclohexyl ketone

Methyl cyclohexyl ketone

Diphenyl ketone

Cyclohexanone

Methyl phenyl ketone

Acetylacetone

1,2-cyclohexandione

1,3-cyclohexandione and

2,4,6,8-n-nonatetraone.

L is preferably selected from compounds of the group having thefollowing general formulae: ##STR8## wherein R, R', R" and R'" arehydrocarbyl radicals independently selected from the group consisting ofhydrogen, C₁ to C₂₀ alkyl, C₃ to C₂₀ cycloalkyl, C₆ to C₂₀ aryl and C₇to C₂₀ aralkyl and alkaryl radicals and X is a member selected from thegroup consisting of N, P, As and Sb, with P being preferred.

Thus, compounds within the scope of this definition include:

Cyclopentadiene

Methyl cyclopentadiene

Ethyl cyclopentadiene

Butyl cyclopentadiene

Phosphine

Trimethyl phosphine

Triethyl phosphine

Tributyl phosphine

Methyl diphenyl phosphine

Triphenyl phosphine

Butyl diphenyl phosphine

Triethylamine

Triethylarsine, and

Triethylstibine.

L may also represent more than one ligand independently selected fromthe above group. For example, in the compound

[C₄ H₈ O]₄ Mg[Mo(CO)₂ (PCH₃ (C₆ H₅)₂ C₅ H₅ ]₂

wherein a would equal 2, and L would equal methyl diphenyl phosphine andcyclopentadiene.

The above-mentioned novel compounds can be prepared by any of fourmethods:

1. A slight excess of MeX₂ (wherein Me is a Group IIA metal and X is Cl,Br or I, preferably Cl or Br) dissolved in tetrahydrofuran (THF) can beadded to the Na derivative of the transition metal carbonyl complex,with agitation. After the reaction is complete, the crude reactionmixture is filtered to remove the insoluble NaX formed. The filtrate isconcentrated with reduced pressure and the magnesium transition metalcompound is precipitated by adding n-pentane. The solid product ispurified by recrystallization from benzene. Examples of some sodiumderivatives of transition carbonyl complexes include:

Na.sup.⊕ Fe(CO)₂ (C₅ H₅).sup.⊖

Na.sup.⊕ Mo(CO)₃ (C₅ H₅).sup.⊖

Na.sup.⊕ Co(CO)₄.sup.⊖

Na.sup.⊕ Co(CO)₃ (P(nC₄ H₉)₃)).sup.⊖

Examples of reaction pathways: ##STR9##

(2) A solution of a transition metal carbonyl derivative of Hg isreacted with the Group IIA metal. The crude reaction mixture is filteredto remove the free mercury formed by the metal exchange reaction. Themagnesium transition metal compound is isolated from the filtrate as in(1) above. Examples of some Hg derivatives of transition metal carbonylcomplexes include:

Hg(Fe(CO)₂ C₅ H₅)₂

Hg(Co(CO)₄)₂

Hg(Co(CO)₃ P(C₆ H₅)₃)₂

Hg(Mo(CO)₃ C₅ H₅)₂

Typical reaction pathway: ##STR10##

(3) The same procedure as in (2), except that a transition metalcarbonyl halide compound is used instead of the mercury derivative. TheGroup IIA halide formed is removed by filtration. Examples of sometransition metal carbonyl halides include:

(C₅ H₅) Fe(CO)₂ I, (C₅ H₅)Fe(CO)₂ Br

(C₅ H₅) Mo(CO)₃ I

(C₅ H₅) Mo(P(nC₄ H₉)₃)(CO)₂ I

(C₅ H₅)Ni(CO)I

((C₆ H₅)₃ Rh(CO)Cl

(CO)₅ MnBr

Typical reaction pathway: ##STR11##

(4) An amalgam of the Group IIA metal is reacted with a dimeric metalcarbonyl complex yielding the above mentioned novel compounds. Examplesof some dimeric metal carbonyl complexes include:

(Fe(CO)₂ (C₅ H₅))₂

(Mo(CO)₃ (C₅ H₅))₂

((C₅ H₅)Ni(CO))₂

Co₂ (CO)₈

Co₂ (CO)₆ (P(nC₄ H₉)₃)₂

Mn₂ (CO)₁₀

(W(CO)₃ C₅ H₅)₂

Typical reaction pathway: ##STR12##

All of the above procedures are carried out under an inert atmosphere,generally nitrogen. The reaction temperature range varies from -40° C.to 300° C., preferably between 0° C. and 120° C., and most preferablybetween room temperature and 100° C.

The reaction of the Group IIA metal (and also the halide or amalgam asshown above) and the transition metal carbonyl complex normally takesplace in a solvent. Inert solvents such as benzene, toluene, n-pentane,etc., can be used as long as there is also present enough Lewis basesuch as pyridine, tetrahydrofuran, etc., to coordinate with the GroupIIA metal, as noted above. Preferably, the reaction is carried out inthe presence of a substantial excess of the Lewis base, and if thereactants are soluble in the Lewis base, the solvent can consistentirely of the Lewis base. It should be noted that the solubility ofthe Group IIA-transition metal carbonyl complex in hydrocarbon solventsis dependent on the nature of the Lewis base adduct. For example, inbenzene the solubility of the Lewis acid adducts increase in thefollowing order: tetrahydrofuran, pyridine, andtetramethyldiethylenediamine.

The molar ratio of Group IIA metal and transition metal carbonyl complexis preferably greater than 1, since traces of oxygen will causeoxidation of the Group IIA-transition metal carbonyl complex accordingto the following reaction:

    B.sub.x Me(M).sub.2 +1/2O.sub.2 →xB+MeO+M-M

wherein the symbols have the meanings ascribed previously.

If the Group IIA metal is in excess, it will convert the transitionmetal carbonyl dimer back to the desired product according to thefollowing reaction: ##STR13## The MeO is easily separable since it willusually be a filterable solid. Also, if the transition metal carbonylcomplex is in excess, the unreacted portion will be difficult to removefrom the desired Group IIA-transition metal carbonyl compound.

For the above reasons, the mole ratio of Group IIA metal to transitionmetal usually ranges from 1 to 100 with a range of 1.1 to 10 preferred,and 1.1 to 3.3 specially preferred. It should be noted that if one doesnot intend to isolate the product, or does not find the economics, ofseparating the desired products from the reactants unattractive, lowerratios may be used.

The novel compounds described herein may be used as a catalyst in avariety of chemical processes in addition to the carbonylation process.For example, unsaturated organic compounds can be hydrogenated to givethe corresponding saturated derivatives. These catalysts are also usefulfor hydroformylation reactions wherein an alkene is reacted with carbonmonoxide and hydrogen to form aldehydes and alcohols. Excellentselectivity has been shown by the tetrakis tetrahydrofuran adduct of amagnesium-dicobalt hexacarbonyl bismethyldiphenylphosphine complex inthe conversion of 1-hexene to heptaldehydes. The conversion was >99%with a selectivity of 87%. This conversion is run at elevated pressures,preferably from 1,500 to 3,000 psi. Reaction temperatures will rangefrom 50° C. to 200° C., with a range of 100° C. to 150° C. preferred.Ratio of H₂ to CO used will vary with reaction conditions; preferably a1 to 1 ratio is maintained. The catalyst concentration will range from0.01 to 20% based on the weight feed, with 0.05 to 10 % preferred.

The novel compounds described herein have also shown utility in thepreparation of cyclic dimers and trimers of butadiene. In particular,cyclododecatriene may be produced by the trimerization of butadiene.

The above uses are in addition to the carbonylation of alkanols tocarboxylic acid esters by use of the novel catalysts described above.

Reactions which utilize the novel catalyst will usually be run in theliquid phase; i.e., one advantageous characteristics of the catalyst ofthis invention is that its solubility in organic solvents can be variedby the proper choice of Lewis base adduct, thereby allowing the skilledartisan to design a homogeneous or heterogeneous catalyst system. Thereactions which utilize the novel catalyst will be run at temperaturesranging from -50° C. to 500° C. and pressures ranging fromsubatmospheric to superatmospheric, according to the specific reaction.The proper temperatures and pressure conditions will be apparent to oneskilled in the art. In a like manner, the reaction times and thecatalyst concentrations will vary according to the specific reaction,and will also be apparent to the skilled artist.

The following examples serve to more fully describe the manner of makingand using the above-described invention, as well as to set forth thebest modes contemplated for carrying out various aspects of theinvention. It is understood that these examples in no way serve to limitthe true scope of this invention, but rather, are presented forillustrative purposes.

Preparation of the Novel Catalyst

In the preparation of the novel catalyst, all reactions were carried outunder a nitrogen atmosphere.

EXAMPLE A Preparation of [C₄ H₈ O]₂ Mg[Fe(CO)₂ C₅ H₅ ]₂ Method (1)

0.2 gms. MgBr₂ dissolved in 15 mls. of tetrahydrofuran was addeddropwise to a solution of 0.4 gms. Na[Fe(CO)₂ C₅ H₅ ] in 30 ml. oftetrahydrofuran, in a 100 ml. flask equipped with a magnetic stirrer.The NaFe(CO)₂ C₅ H₅ had been prepared by the reductive cleavage of [C₅H₅ Fe(CO)₂ ]₂ with 1% sodium amalgam. This mixture was allowed to stirat room temperature for 24 hours. The crude reaction mixture wasfiltered and reduced pressure to remove the insoluble salts formedduring the reaction. The filtrate was concentrated with reducedpressure. The concentrate was slowly poured into n-pentane whichaffected the precipitation of a yellow-orange solid. The crude productwas recrystallized several times from benzene and vacuum dried. The puresolid is a bright yellow solid and is extremely air sensitive. Uponatmospheric exposure the magnesium-transition metal compound isquantitatively oxidized to [C₅ H₅ Fe(CO)₂ ]₂ and MgO. The stoichiometryof the complex was established by nmr and elemental analyses. Thecomposition of all of the following novel products were determined by acombination of nmr and elemental analysis.

Calculated for [C₄ H₈ O]₂ Mg[Fe(CO)₂ C₅ H₅ ]₂ : 50.5% C, 4.97% H, 4.59%Mg, 21.6% Fe and a molecular weight of 522.

Found for reaction product: 46.7% C, 4.83% H, 4.64% Mg, 22.5% Fe and amolecular weight of 528 benzene.

Elemental analyses, molecular weight and color data for the novelcatalyst compounds synthesized in this example and following examplesare given in Table I.

It should be noted that the halide products postulated by Burlich andUlmer were not produced.

                                      TABLE I                                     __________________________________________________________________________    ANALYTICAL DATA, MOLECULAR WEIGHTS.sup.(a) AND COLORS                         __________________________________________________________________________                         Calculated %                                             Compound             Color                                                                             C   H   Mg  Me.sup.1                                                                          P   N                                __________________________________________________________________________    (THF).sub.2 Mg(Fe(CO).sub.2 C.sub.5 H.sub.5).sub.2                                                 Yellow                                                                            50.5                                                                              4.97                                                                              4.59                                                                              21.6                                                                              --  --                               (Pyridine).sub.2 Mg[Fe(CO).sub.2 C.sub.5 H.sub.5 ].sub.2                                           Yellow                                                                            53.6                                                                              3.74                                                                              4.54                                                                              20.8                                                                              --  5.24                                                  Light                                                    (THF).sub.4 Mg[Mo(CO).sub.2 PCH.sub.3 (C.sub.6 H.sub.5).sub.2 C.sub.5         H.sub.5 ].sub.2      Yellow                                                                            58.6                                                                              5.83                                                                              2.10                                                                              16.8                                                                              5.41                                                                              --                               (THF).sub.4 Mg[Mo(CO).sub.2 P(C.sub.4 H.sub.9).sub.3 C.sub.5 H.sub.5          ].sub.2              Yellow                                                                            56.4                                                                              8.35                                                                              2.11                                                                              16.7                                                                              5.39                                                                              --                               (Pyridine).sub.4 Mg[Co(CO).sub.4 ].sub.2                                                           Yellow                                                                            49.3                                                                              2.96                                                                              3.42                                                                              17.3                                                                              --  8.22                             (THF).sub.4 Mg[Co(CO).sub.3 PCH.sub.3 (C.sub.6 H.sub.5).sub.2 ].sub.2                              Yellow                                                                            57.6                                                                              5.83                                                                              2.40                                                                              11.8                                                                              6.20                                                                              --                                                    Yellow                                                   (THF).sub.4 Mg[Co(CO).sub.3 P(C.sub.4 H.sub.9).sub.3 ].sub.2                                       Green                                                                             55.2                                                                              8.60                                                                              2.43                                                                              11.8                                                                              6.20                                                                              --                               (Pyridine).sub.4 Mg[Co(CO).sub.3 PCH.sub.3 (C.sub.6 H.sub.5).sub.2            ].sub.2              Yellow                                                                            60.6                                                                              4.48                                                                              2.38                                                                              11.6                                                                              5.99                                                                              5.46                             (TMEDA).sub.2 Mg[Co(CO).sub.3 PCH.sub.3 (C.sub.6 H.sub.5).sub.2 ].sub.2                            Yellow                                                                            56.1                                                                              6.15                                                                              2.58                                                                              12.5                                                                              --  --                               (THF).sub.4 Mg(Mn(CO).sub.5).sub.2                                                                 Yellow                                                                            44.5                                                                              4.56                                                                              3.46                                                                              15.7                                                                              --  --                               (THF).sub.4 Mg[Mn(CO).sub.4 PCH.sub.3 (C.sub.6 H.sub.5).sub.2 ].sub.2                              Yellow                                                                            57.4                                                                              5.54                                                                              2.32                                                                              10.5                                                                              5.94                                                                              --                                                    Light                                                    (Pyridine).sub.4 Mg[Mn(CO).sub.5 ].sub.2                                                           Green                                                                             49.3                                                                              2.94                                                                              3.29                                                                              15.1                                                                              --  7.67                             __________________________________________________________________________                                           Molecular                                                   Found %           Weight                                                      C  B  Mg Me'                                                                              P  N  Calc.                                                                             Found                              __________________________________________________________________________    (THF).sub.2 Mg(Fe(CO).sub.2 C.sub.5 H.sub.5).sub.2                                                 46.7                                                                             4.83                                                                             4.64                                                                             22.5                                                                             -- -- 522 228                                (Pyridine).sub.2 Mg[Fe(CO).sub.2 C.sub.5 H.sub.5 ].sub.2                                           54.9                                                                             5.16                                                                             4.82                                                                             17.7                                                                             -- 5.76                                                                             536 498                                (THF).sub.4 Mo(CO).sub.2 PCH.sub.3 (C.sub.6 H.sub.5).sub.2 C.sub.5            H.sub.5 ].sub.2      58.3                                                                             5.61                                                                             3.09                                                                             17.4                                                                             6.25                                                                             -- --  --                                 (THF).sub.4 Mg[Mo(CO).sub.2 P(C.sub.4 H.sub.9).sub.3 C.sub.5 H.sub.5          ].sub.2              55.9                                                                             8.37                                                                             2.37                                                                             18.1                                                                             5.51                                                                             -- 1150                                                                              599                                (Pyridine).sub.4 Mg[Co(CO).sub.4 ].sub.2                                                           49.4                                                                             3.26                                                                             2.91                                                                             17.1                                                                             -- 7.79                                                                             682 665                                (THF).sub.4 Mg[Co(CO).sub.3 PCH.sub.3 (C.sub.6 H.sub.5).sub.2 ].sub.2                              55.9                                                                             6.01                                                                             2.36                                                                             11.1                                                                             6.26                                                                             -- --  --                                 (THF).sub.4 Mg[Co(CO).sub.3 P(C.sub.4 H.sub.9).sub.3 ].sub.2                                       54.6                                                                             8.74                                                                             2.45                                                                             11.4                                                                             5.99                                                                             -- 1002                                                                              310                                (Pyridine).sub.4 Mg[Co(CO).sub.3 PCH.sub.3 (C.sub.6 H.sub.5).sub.2            ].sub.2              58.6                                                                             4.51                                                                             2.51                                                                             11.7                                                                             5.69                                                                             5.41                                                                             --  --                                 (TMEDA).sub.2 Mg[Co(CO).sub.3 PCH.sub.3 (C.sub.6 H.sub.5).sub.2 ].sub.2                            53.5                                                                             6.14                                                                             2.66                                                                             12.9                                                                             -- -- --  --                                 (THF).sub.4 Mg(Mn(CO).sub.5).sub.2                                                                 43.7                                                                             5.26                                                                             3.91                                                                             13.6                                                                             -- -- --  --                                 (THF).sub.4 Mg[Mn(CO).sub.4 PCH.sub.3 (C.sub.6 H.sub.5).sub.2 ].sub.2                              56.6                                                                             6.01                                                                             2.55                                                                             9.79                                                                             6.19                                                                             -- --  --                                 (Pyridine).sub.4 Mg[Mn(CO).sub.5 ].sub. 2                                                          47.6                                                                             3.11                                                                             2.91                                                                             14.9                                                                             -- 7.72                                                                             --  --                                 __________________________________________________________________________     .sup.(a) Molecular weights were determined cryoscopically employing           benzene solutions.                                                       

Method (2)

A solution containing 5.5 gm of H₆ [Fa(CO)₂ C₅ H₅ ]₂ in 75 ml oftetrahydrofuran was added to a heavy walled reaction tube (equipped witha teflon vacuum stopcock) containing 0.5 gm of 200 mesh magnesium metal.The metal and reaction tube had previously been flamed out under avacuum of 10⁻⁴ mm. The reaction tube was sealed under vacuum and placedin an oil bath held at 85° C. After 24 hours the tube was broken and thecontents filtered. The filtrate was concentrated with reduced pressure.The concentrate was poured into n-pentane which caused the precipitationof a yellow solid. The solid was collected and washed several times witha 25:75 mixture of benzene and n-pentane to remove any unreactedHg[Fe(CO)₂ C₅ H₅ ]₂. The final purification procedure wasrecrystallization from benzene. The yield was 4.2 gm of [C₄ H₈ O]₂Mg[Fe(CO)₂ C₅ H₅ ]₂.

Method ( 3)

1.0 gm of magnesium powder (200 mesh) was placed in a heavy wallreaction tube. The tube and its contents were flamed out at 10⁻⁴ mm. Asolution of 6.0 gm of C₅ H₅ Fe(CO)₂ I in 75 ml. of tetrahydrofuran wasplaced in the reaction tube. After a short induction period the reactionbecame exothermic enough to warm tetrahydrofuran to its reflux point.The initial red solution quickly turned dark yellow and the reactionappeared complete in 15 or 20 minutes. The crude reaction mixture wasfiltered. MgI₂ was collected on the filter and discarded. The filtratewas concentrated with reduced pressure. The concentrate was flooded withn-pentane causing the immediate precipitation of a yellow solid. Thecrude reaction product was collected and washed with a 50:50 mixture ofn-pentane-ether to remove any unreacted C₅ H₅ Fe(CO)₂ I. The remainingyellow solid was then recrystallized several times from benzene. Theyield was very nearly quantitative.

Method (4)

In a 250 ml., 1-neck, round bottom flask 50 gm of mercury and 0.6 gm of200 mesh magnesium powder were rapidly stirred to form the amalgam. Theamalgam was allowed to cool to room temperature. To the amalgam wasadded a solution containing 5.0 gm of [C₅ H₅ Fe(CO)₂ ]₂ in 75 ml. oftetrahydrofuran. The resulting solution was deep red. The flask wasstoppered and the mixture was stirred vigorously. After 18 hours thesolution had become a yellow-green. The reaction mixture was filtered tofree it from the amalgam. The filtrate was concentrated with reducedpressure to approximately 25 ml. The concentrated tetrahydrofuransolution was flooded with n-pentane, yielding a yellow solid. The yellowsolid was recrystallized from benzene and vacuum dried. The yield was7.2 gm of [C₄ H₈ O]₂ Mg[Fe(CO)₂ C₅ H₅ ]₂.

EXAMPLE B Preparation of (C₅ H₅ N)₂ Mg[Fe(CO)₂ C₅ H₅ ]₂

In a 250 ml., 1-neck round bottom flask an amalgam consisting of 50 gmof mercury and 0.6 gm of powdered magnesium (200 mesh) was prepared. Asolution containing 6.7 gm of pyridine in 125 ml. of benzene was addedto the flask. To the benzene-pyridine solution was added 5.0 gm of [C₅H₅ Fe(CO)₂ ]₂. The resultant solution was deep red. After 18 hours thesolution had become a reddish-yellow with a considerable amount of ayellow solid suspended in the solution. The reaction mixture wasfiltered and an orange-yellow solid was collected. The collected solidwas taken up in benzene and filtered to free it of magnesium amalgam.The filtrate was concentrated with reduced pressure. The concentrate wasflooded with n-pentane, knocking out of solution a bright yellow solid.The solid was recrystallized from benzene and then vacuum dried. Theyield was nearly quantitative. The bright yellow solid is air sensitiveand is quantitatively oxidized to [C₅ H₅ Fe(CO)₂ ]₂ and MgO uponexposure to the air. The stoichiometry of the complex was established bynmr measurements and elemental analysis.

EXAMPLE C Preparation of (C₄ H₈ O)₄ Mg[Mo(CO)₃ C₅ H₅ ]₂

This compound was prepared by a method similar to that used in thepreparation of [C₄ H₈ O]₂ Mg[Fe(CO)₂ C₅ H₅ ]₂ described in Method 3 ofExample A. C₅ H₅ Mo(CO)₃ I was prepared by cleaving themolybdenum-molybdenum bond of [Mo(CO)₃ C₅ H₅ ]₂ with I₂ intetrahydrofuran solution. The magnesium-molybdenum compound is white andis only sparingly soluble in tetrahydrofuran. The stoichiometry of thecompound (C₄ H₈ O)₄ Mg[Mo(CO)₃ C₅ H₅ ]₂ was established by nmrmeasurements (solutions in d-acetonitrile) and elemental analysis. Thesame product was also prepared by cleaving (Mo(CO)₃ C₅ H₅)₂ withmagnesium amalgam in tetrahydrofuran solution.

EXAMPLE D Preparation of (C₅ H₅ N)₄ Mg[Mo(CO)₃ C₅ H₅ ]₂

This compound was prepared by a method similar to that used in thepreparation of the pyridine adduct, (C₅ H₅ N)₂ Mg[Fe(CO)₂ C₅ H₅ ]₂,described in Example B above. The molybdenum cyclopentadienyltricarbonyl dimer, [C₅ H₅ Mo(CO)₃ ]₂, was cleaved with magnesium amalgamin benzene solution in the presence of excess pyridine. The solubilityof (C₅ H₅ N)₄ Mg[Mo(CO)₃ C₅ H₅ ]₂ in benzene was found to be somewhatgreater than the tetrakis tetrahydrofuran adduct. The pure solid is alight green. The stoichiometry of the compound was determined by nmrmeasurements upon d-acetonitrile solutions.

EXAMPLE E Preparation of (C₄ H₈ O)₄ Mg[Mo(CO)₂ (PCH₃ (C₆ H₅)₂)C₅ H₅ ]₂

0.2 gm of magnesium powder (200 mesh) was flamed out in a heavy walledreaction tube (equipped with a teflon stopcock) under a vacuum of 10⁻⁴mm. A solution containing 4.0 gm of C₅ H₅ Mo(CO)₂ (CH₃ P(C₆ H₅)₂)I(prepared by reacting equimolar quantities of C₅ H₅ Mo(CO)₃ I and CH₃P(C₆ H₅)₂ in benzene solution) in 25 ml. of tetrahydrofuran was added tothe reaction tube. The stopcock was closed and the tube was placed in anoil bath held at 50° C. to 60° C. After 18 hours the bulk of themagnesium powder had been consumed and an off-white solid had come outof solution. The reaction mixture was filtered leaving MgI₂ on the frit.The filtrate was concentrated with reduced pressure. A yellow solid wasobtained by flooding the tetrahydrofuran concentrate with n-pentane.This solid was washed with a 50:50 mixture of benzene and n-pentane toremove any unreacted starting material. Nmr and elemental analysis haveshown this compound to be the tetrakis tetrahydrofuran adduct. Thetetrakis tetrahydrofuran adduct was also obtained in good yield bysubstituting a magnesium amalgam for the magnesium powder. The amalgamreaction could be carried out at room temperature.

EXAMPLE F Preparation of (C₄ H₈ O)₄ Mg[Co(CO)₄ ]₂

This compound was prepared by cleaving the cobalt-cobalt bond in Co₂(CO)₈ with magnesium amalgam in tetrahydrofuran solution. The darkyellow product is extremely air sensitive and is nearly insoluble in allcommon organic solvents. The air oxidation products are MgO and Co₂(CO)₈. The compound's insolubility would not allow a recrystallization,so purification was effected by repeated washings with a 50:50tetrahydrofuran-n-pentane mixture. The washed solid was extracted withtetrahydrofuran yielding a dark yellow solution (solubility ca. 1 gm/l).A dark yellow solid was isolated by adding n-pentane to the saturatedtetrahydrofuran solution. Infrared measurements showed the compound tobe free of impurities.

EXAMPLE G Preparation of [(C₅ H₅ N)₄ Mg[Co(CO)₄ ]₂

This compound was prepared by cleaving Co₂ (CO)₈ with magnesium amalgamin the presence of excess pyridine in benzene solution. The compoundexhibits good solubility in hydrocarbon solvents and was recrystallizedfrom benzene. Elemental analyses were in good agreement with thetetrakis pyridine formulation. The analytically pure compound is lightyellow. The compound is air sensitive but less so than (C₄ H₈ O)₄Mg[Co(CO)₄ ]₂.

EXAMPLE H Preparation of (C₄ H₈ O)₄ Mg[Co(CO)₃ PCH₃ (C₆ H₅)₂ ]₂

This compound was prepared by cleaving the cobalt-cobalt bond in Co₂(CO)₆ (CH₃ P(C₆ H₅)₂)₂ with a magnesium amalgam in tetrahydrofuransolution. Co₂ (CO)₆ (CH₃ P(C₆ H₅)₂)₂ was prepared by allowing twoequivalents of CH₃ P(C₆ H₅)₂ to react with one equivalent of Co₂ (CO)₈in refluxing benzene. The substitution reaction was complete in 24hours. (C₄ H₈ O)₄ Mg[Co(CO)₃ CH₃ P(C₆ H₅)₂ ]₂ was obtained analyticallypure by repeated recrystallizations from benzene. The pure compound isyellow. The stoichiometry of the compound was established by elementalanalyses and nmr measurements.

EXAMPLE I Preparation of (C₅ H₅ N)₄ Mg[Co(CO)₃ PCH₃ (C₆ H₅)₂ ]₂

This was prepared by reducing a benzene solution of Co₂ (CO)₆ (PCH₃ (C₆H₅)₂)₂ with magnesium amalgam in the presence of a two-fold excess ofpyridine. A light yellow, air sensitive solid was isolated byconcentrating the filtered reaction mixture with reduced pressure andflooding the concentrate with n-pentane. The product was purified byrecrystallizing from benzene. The yield was nearly 100%. The molecularformula was obtained by nmr measurements and elemental analyses.

EXAMPLE J Preparation of [(CH₃)₂ NCH₂ CH₂ N(CH₃)₂ ]₂ Mg[Co(CO)₃ PCH₃ (C₆H₅)₂ ]₂

This light yellow compound was obtained in a manner very similar to thatused in preparing (C₅ H₅ N)₄ Mg[Co(CO)₃ PCH₃ (C₆ H₅)₂ ]₂ but withtetramethylethylenediamine being substituted for pyridine. Thestoichiometry of the compound was established by elemental analyses andnmr measurements.

EXAMPLE K Preparation of (C₄ H₈ O)₄ Mg[Mn(CO)₂ ]₂

0.1 moles of Mn₂ (CO)₁₀ in tetrahydrofuran was reduced with excess 1%magnesium amalgam. After 18 hours the reaction mixture was filtered anda yellow filtrate was obtained. The filtrate was concentrated withreduced pressure. The concentrate yielded a yellow solid upon additionof n-pentane. The air sensitive yellow solid was found to be onlysparingly soluble in benzene. Purification was effected by washing thesolid with a 50:50 benzene-n-pentane mixture to remove any unreacted Mn₂(CO)₁₀. The washed solid was redissolved in tetrahydrofuran, filteredand reprecipitated with n-pentane. This redissolving-reprecipitationprocess was repeated several times. The yield was very nearlyquantitative. Elemental analysis established the compound as thetetrakis tetrahydrofuran adduct. Note that the elemental analysis (TableI) establishes that the bis-adduct is not formed, as claimed by Hieberet al. Infrared spectral studies also confirm that the tetrakis adductis the only product formed.

EXAMPLE L Preparation of (C₄ H₈ O)₄ Mg[Mn(CO)₄ PCH₃ (C₆ H₅)₂ ]₂

To a slurry of (C₄ H₈ O)₄ Mg(CO)₅)₂ in toluene a two molar equivalent ofCH₃ P(C₆ H₅)₂ was added and the mixture was refluxed for two hours.While concentrating the reaction mixture with reduced pressure, a yellowsolid came out of solution and was collected by filtration. Thestoichiometry of the phosphine derivative was established by elementalanalysis and nmr spectroscopy. The addition of phosphine was nearlyquantitative. The phosphine derivative has a much higher solubility inaromatic solvents than the unsubstituted compound.

EXAMPLE M Preparation of (C₅ H₅ N)₄ Mg[Mn(CO)₅ ]₂

0.1 moles of Mn₂ (CO)₁₀ in benzene containing a small stoichiometricexcess of pyridine was reduced with a 1% magnesium amalgam. After 18hours the reaction mixture was filtered yielding a light green filtrate.Solvent was removed from the filtrate until solid started to come out ofsolution. N-pentane was added to the concentrated solution, resulting ina nearly quantitative recovery of the desired product. Therecrystallized compound is light green. The stoichiometry of the airsensitive compound was established by elemental analysis.

Use of the Novel Catalyst In the Carbonylation of Alkanols to CarboxylicAcid Esters EXAMPLE 1--Use of Cobalt Catalyst to Obtain Methyl Acetate

(THF)₄ Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂ +CH₃ I catalyst system

Feed: 2.0 gm (2 mmoles)(THF)₄ Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂, 0.5 ml (8 mmoles)CH₃ I, 30 ml methanol, 70 ml benzene.

Reaction conditions: 800 psi CO pressure, 120° C., 48 hours.

Products: 37% conversion to methyl acetate, trace amount of CH₃ OCH₃

Note a molar rato of cocatalyst/catalyst of 4 resulted in substantiallyno ether formation.

EXAMPLE 2--Carbonylation of Ethanol

(THF)₄ Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂ +CH₃ I catalyst system

Feed: 2.0 gm (2 mmoles)(THF)₄ Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂, 0.5 ml (8 mmoles)CH₃ I, 100 ml ethanol.

Reaction conditions: 600 psi CO pressure, 200° C., 48 hours.

Products: 15% conversion to ethyl propionate, 6.7% conversion to ethylether.

EXAMPLE 3--Mixed Alcohol Carbonylation Process

(THF)₄ Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂ +CH₃ I catalyst systems

Feed: 0.5 gm (0.5 mmoles)(THF)₄ Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂, 0.5 ml (8mmoles) CH₃ I, 30 ml isopropanol, 40 ml benzene, 30 ml methanol.

Reaction conditions: 800 psi CO pressure, 185° C. 72 hours.

Products: wt. %, methanol 1, isopropanol 20, methyl acetate 15,isopropyl acetate 25, isopropyl ether 5, methyl isopropyl ether 20,methyl ether 5.

Example 3 is typical of mixed alcohol runs where unsymmetrical ethersand lower alcohol acyl esters are preferentially formed.

The following tables summarize the effects of changing the temperature,carbon monoxide pressure and cocatalysts on the ability of (THF)₄Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂ to catalyze the carbonylation of methanol tomethyl acetate.

EXAMPLE 4--The effect of Temperature on the Production of ##STR14## fromCH₃ OH Feed: 90 ml CH₃ OH, 10 ml C₆ H₆, 1.0 mmole (THF)₄ Mg[Co(CO)₃ P(C₄H₉)₃ ]₂, 8 mmoles CH₃ I, 4000 psi Co pressure, 4 hour reaction time.

    ______________________________________                                                     Tempera-                                                                                   ##STR15##                                           Experiment  ture, °C.                                                                           produced                                             ______________________________________                                        A           100           3.5                                                 B           150          21.8                                                 C           175          29.6                                                 D           200          14.4                                                 ______________________________________                                    

EXAMPLE 5--The Effect of Pressure on the Production of ##STR16## fromCH₃ OH Feed: 90 ml CH₃ OH, 10 ml C₆ H₆, 1.0 mmole (THF)₄ Mg[Co(CO)₃ P(C₄H₉)₃ ]₂, 8.0 mmoles CH₃ I, 175° C., 4 hour reaction time.

    ______________________________________                                                                    ##STR17##                                         Experiment  Pressure(psi)  produced                                           ______________________________________                                        A            500           2.0                                                B           1000           4.5                                                C           4000           29.6                                               ______________________________________                                    

EXAMPLE 6--The Effect of CH₃ I Concentration on the Production of##STR18## from CH₃ OH Feed: 90 ml CH₃ OH, 10 ml C₆ H₆, 1.0 mmole (THF)₄Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂, 1000 psi Co pressure, 175° C., 20 hour reactiontime

    ______________________________________                                         Exper-  CH.sub.3 I                                                                               ##STR19##     CH.sub.3 OHml                               iment   (mmole)    produced      consumed                                     ______________________________________                                        A       1.6        0.5           1.2                                          B       8.0        22.4          30.0                                         C       16.0       4.5           45.0*                                        D       48.0       1.2           90.*                                         ______________________________________                                         *At high CH.sub.3 I concentration CH.sub.3 OH is dehydrated to CH.sub.3       OCH.sub.3.                                                               

Note that at a CO pressure of 1000 psi optimum methyl acetate productionbegins to decline at a cocatalyst-catalyst molar ratio of more than 8 incontradistinction where lower pressures and a similar ratioproduces >95% conversion to dimethyl ether. This experiment demonstratesthe interdependency of the cocatalyst-catalyst ratio and CO pressurevariables.

EXAMPLE 7--The Effect of Cocatalyst on the Production of ##STR20## fromCH₃ OH Feed: 90 ml CH₃ OH, 10 ml C₆ H₆, 1.0 mmole (THF)₄ Mg[Co(CO)₃ P(C₄H₉)₃ ]₂, 4000 psi CO pressure, 175° C., 4 hours reaction time

    ______________________________________                                         Cocatalyst(mmole)                                                                            ##STR21##                                                     ______________________________________                                        LiI (4.0)      1.0                                                            None           2.0                                                            I.sub.2 (2.0)  5.2                                                            HI (4.0)       6.6                                                            CH.sub.3 I (16.0)                                                                            19.8                                                           CH.sub.3 I (8.0)                                                                             29.6                                                           CH.sub.3 CH.sub.2 I (8.0)*                                                                   17.5                                                           C.sub.6 H.sub.5 I (8.0)*                                                                     22.3                                                           CH.sub.3 I (8.0)*                                                                            21.4                                                           ______________________________________                                         *1000 psi CO                                                             

Note that longer reaction times were required at lower pressure toproduce comparable conversion level, i.e., CH₃ I., 18 hours, CH₃ CH₂I..19 hours, C₆ H₅ I..90 hours.

EXAMPLE 8--Effect of Catalyst on the Carbonylation of Methanol to MethylAcetate

Feed: 90 ml (2.22 moles) CH₃ OH, 10 ml (0.11 mole) benzene

Reaction conditions: 175° C., 1000 psi

                                      TABLE II                                    __________________________________________________________________________                     Cocatalyst                                                                          Reaction Time                                                                         %     %                                        Catalyst (mmole) (mmole)                                                                             (Hour)  Conversion                                                                          Selectivity.sup.(a)                      __________________________________________________________________________    (C.sub.4 H.sub.8 O).sub.4 Mg[Co(CO).sub.3 P(C.sub.4 H.sub.9).sub.3            ].sub.2          CH.sub.3 I (8.0)                                                                    19      28      99+.sup.(b)                            (2.0)                                                                         (C.sub.4 H.sub.8 O).sub.4 Mg[Co(CO).sub.3 P(C.sub.4 H.sub.9).sub.3            ].sub.2          CH.sub.3 I (8.0)                                                                    18      24    85                                       (1.0)                                                                         (C.sub.4 H.sub.8).sub.4 Mg(Mn(CO).sub.5).sub.2                                                 CH.sub.3 I (8.0)                                                                    19      trace --                                       (2.8)                                                                         [(C.sub.4 H.sub.9).sub.3 P].sub.3 Cu--Co(CO).sub.3 P(C.sub.4 H.sub.9).sub.    3                CH.sub.3 I (8.0)                                                                    16      10    24                                       (2.0)                                                                         NaCo(CO).sub.3 P(C.sub.4 H.sub.9).sub.3                                                        CH.sub.3 I (8.0)                                                                    19      5.0   14                                       (2.0)                                                                         Co.sub.2 (CO).sub.6 [P(C.sub.4 H.sub.9).sub.3 ].sub.2                                          CH.sub.3 I (6.0)                                                                    20      9.0   37                                       (1.0)                                                                         Co.sub.2 (CO).sub.8                                                                            CH.sub.3 I (8.0)                                                                    21      3.5     6.4                                    (1.0)                                                                         Co.sub.2 (CO).sub.6 (P(C.sub.4 H.sub.9).sub.3).sub.2                                           CH.sub.3 I (8.0)                                                                    19      3.5   10                                       (1.0)                                                                         Co(C.sub.5 H.sub.7 O.sub.2).sub.3                                                              CH.sub.3 I (8.0)                                                                    67      16    23                                       (2.0)                                                                         __________________________________________________________________________     .sup.(a) Additional product was dimethyl ether                                .sup.(b) No dimethyl ether was collected in the offgases vented through a     toluene bath at -80° C.                                           

As can be seen from Table II, the magnesium cobalt carbonyls are muchsuperior catalysts with respect to both product selectivity and catalystactivity than the other compounds tested. The low activity and productselectivity exhibited by Co₂ (CO)₆ (P(C₄ H₉)₃)₂ strongly suggests thatthe novel compounds, i.e., (C₄ H₈ O)₂ Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂ complexdoes not decompose under reaction condition into cobalt carbonyl dimer.Since the magnesium-transition metal derivatives contain a polarmetal-metal bond it was suspected that ionic compounds such as NaCo(CO)₃P(C₄ H₉)₃ and [P(C₄ H₉)₃ ]₃ CuCo(CO)₃ P(C₄ H₉)₃ would show comparablecatalytic activity. Table II clearly shows that this is not the case.Additional experimental evidence has suggested that the catalystdifferences between these ionic complexes and the magnesium transitionmetal compounds is directly related to the relative ease of productionof alkyl and hydride intermediate species generated by addition of analkyl iodide cocatalyst.

It has been found that conversions in the range of between 20-40% areobtained in batch autoclave experiments. These results suggest that theextents of the reaction is equilibrium controlled. Recycle experimentshave shown continued catalyst activity thus conversion is not limited bya short catalyst lifetime. The reaction can most likely be forced towardhigher methyl acetate yields by removing water as it is formed.

The absence of detectable amounts of acetic acid in the reaction mixtureby the reaction of methyl acetate with water can be explained by thefact that K (equil.) for the esterification reaction has been found tobe near 16 at 175° C.

To illustrate this point in a typical carbonylation in which 2.2 molesof methanol is converted into 0.40 moles of methyl acetate only 0.0071moles of ##STR22## would be present as equilbrium. Turn over numbers(mole methanol converted/mole catalyst) as high as 10³ have beenobtained.

It has been found that iodine containing compounds are required ascocatalysts in the carbonylation of methanol with the novelmagnesium-transition metal catalysts. As an expansion on the resultsshown in Example 7, a list of the numerous cocatalysts tested inconjunction with (C₄ H₈ O)₄ Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂ are compared inTable III.

Table III suggests that the ability of a cocatalyst to promote thecarbonylation of methanol to methyl acetate varies greatly with the typeof iodine containing compound employed. The activity was found todecrease in the order CH₃ I≈CH₃ CH₂ I>C₆ H₅ I>HI≈I₂ >LiI, thussuggesting that low chain length alkyl iodides are the preferredcocatalyts. The promotional effect of iodine is unique as Cl and Brcontaining compounds such as CH₃ Cl and CH₃ Br were found to beinventive. This result suggests that the carbon-halogen bond strength(C-Cl>C-Br>C-I) plays a dominant role in the primary catalyst activationstep.

The first two entries in Table III suggests that the activity of CH₃ Iis concentration dependent. This was found to be true and is expandedupon in Table IV.

                  TABLE III                                                       ______________________________________                                        EFFECT OF COCATALYST ON THE CARBONYLATION                                     OF METHANOL TO METHYL ACETATE                                                 ______________________________________                                        Feed: 2.22 mole methanol                                                            0.11 mole benzene                                                             1.0 mmole (C.sub.4 H.sub.8 O).sub.4 Mg[Co(CO).sub.3 P(C.sub.4                 H.sub.9).sub.3 ].sub.2                                                  Reaction Conditions: 175° C., 4000 psi CO                                                       % Conver- % Selectiv-                                                         sion to   ity to Methyl                              Cocatalyst                                                                            mmole    t(hr)   Methyl Acetate                                                                          Acetate                                    ______________________________________                                        CH.sub.3 I                                                                            8.0      3.25    29        97                                         CH.sub.3 I                                                                            16.0     4.25    25        74                                         I.sub.2 4.0      5.50    8         27                                         LiI     4.0      4.0     0.6       100                                        HI      4.0      4.25    8         47                                         CH.sub.3 I.sup.a                                                                      8.0      18      24        85                                         CH.sub.3 CH.sub.2 I.sup.a                                                             8.0      19      20        85                                         C.sub.6 H.sub.5 I.sup.a                                                               8.0      90      25        52                                         ______________________________________                                         .sup.a 1000 psi CO.sub.2 longer reaction time required at this lower          pressure to produce comparable conversion levels.                        

                  TABLE IV                                                        ______________________________________                                        EFFECT OF CH.sub.3 I CONCENTRATION ON THE                                     CARBONYLATION OF METHANOL TO                                                  METHYL ACETATE                                                                ______________________________________                                        Feed: 2.22 mole methanol                                                            0.11 mole benzene                                                             1.0 mmole (C.sub.4 H.sub.8 O).sub.4 Mg[Co(CO).sub.3 P(C.sub.4                 H.sub.9).sub.3 ].sub.2                                                  Reaction Conditions: 175° C. 1000 psi CO                                                              % Selectiv-                                    CH.sub.3 I       % Conversion to                                                                             ity to                                         (mmole)  t(hr)   Methyl Acetate                                                                              Methyl Acetate                                 ______________________________________                                        1.6.sup.a                                                                              18      0.0           0.0                                            4.0      18      22            100                                            6.0      18      24            100                                            8.0      18      24            85                                             12.0     18      5.4           15                                             16.0     18      4.5           12                                             48.0.sup.b                                                                             17      0.0           0.0                                            8.0.sup.c                                                                              3.25    29            97                                             16.0.sup.c                                                                             4.25    25            74                                             ______________________________________                                         .sup.a no reaction occurs                                                     .sup.b 100% conversion to CH.sub.3 OCH.sub.3                                  .sup.c 4000 psig. CO employed                                            

Table IV shows the optimum conversion and selectivity to methyl acetateoccurs when the cocatalyst to catalyst ratio is between 4-8 to 1. Whenthis ratio is much less than 4 or much greater than 8 either nocarbonylation occurs at all or complete dehydration to dimethyl ethertakes place. At higher pressures (4000 psig CO) the concentration effectis not as pronounced. This effect is demonstrated by the last twoentries in Table IV.

It has been found that the rates of carbonylation become progressivelyslower as the chain length of the alcohol increases. The seletivity toester products was also found to decrease in the same direction.Secondary alcohols such as isopropyl alcohol presents the problem ofdehydration to olefins. This dehydration can be eliminated by operatingat lower reaction temperatures, i.e., 150° C.

A catalyst system analogous to the catalyst system described in Example10 of U.S. Pat. No. 3,769,329 to Paulik et al was prepared and it wascompared with the catalyst system of the present invention.Specifically, Examples 9 and 10 below demonstrate that a catalyst systemcomprised of a mixture of components equivalent on a molar basis to adiscrete magnesium-transition metal complex of the present invention isnot equivalent and in fact is demonstrated as being an inferior catalystsystem to the catalyst system of the present invention.

EXAMPLE 9

A solution was prepared by adding the following materials (compositecatalyst system) to a feed solution consisting of 90 ml. of methanol and10 ml. of benzene.

Composite Catalyst System

0.53 g. RhCl₃.3H₂ O (2.0 mmoles)

1.1 g. MgI₂ (4.0 mmole)

1.05 g. (C₆ H₅)₃ P (4.0 mmole)

0.15 g. C₄ H₈ O (2.0 mmole)

The solution containing the feed and composite catalyst system wereheated to 175° C. at 800 psig CO pressure for 16 hours. The productsfrom this carbonylation reaction were analyzed to be as follows:

    ______________________________________                                        Methanol conversion  --    59%                                                Product Selectivities:                                                        Methyl Acetate       --     7%                                                Dimethylether        --    93%                                                ______________________________________                                    

When the autoclave was opened, a rhodium mirror had formed on the wallof the glass autoclave liner. This is indicative of the fact that thecomposite catalyst system is not stable under the above reactionconditions. The existence of this rhodium mirror also demonstrates thata discrete Mg-Rh complex is not prepared in situ.

EXAMPLE 10

The following discrete catalyst system was added to the same reactivefeed as shown in Example 9, i.e., 90 ml. methanol and 10 ml. benzene.

Catalyst System:

1.0 gm (0.65 mmole) (C₄ H₈ O)₂ Mg[Rh(CO)₂ (P(C₆ H₅)₃)₂ ]₂

0.5 ml (8.0 mmole) CH₃ I

The solution containing the reactive feed and the discrete catalystsystem were reacted at a temperature of 175° C. at 800 psig CO pressurefor 16 hours. The products from this carbonylation reaction wereanalyzed to be as follows:

    ______________________________________                                        Methanol conversion  --    79%                                                Product selectivities:                                                        Methyl Acetate       --    42%                                                Dimethylether        --    58%                                                ______________________________________                                    

Under the above conditions, the catalyst of the present invention wasfound to be stable, as no rhodium mirror was observed to occur on thewall of the glass autoclave liner.

Examples 9 and 10 clearly demonstrate that the catalyst system of thepresent invention is superior to a composite catalyst prepared on anequimolar basis. The activity and selectivity advantage exhibited by thecatalyst system of the present invention is even more apparent when itis noted that the concentration of rhodium employed in Example 10 isonly 65% as great as that used in the composite system (Example 9).Also, the selectivity of methyl acetate produced by the catalyst systemdisclosed in Example 10 is greatly improved when the CH₃ I/catalystratio is lowered from the value of 12 employed in Example 10.

Other Reactions Using the Novel Catalyst Compounds HydroformylationEXAMPLE 11 Hydroformylation of Propylene

(C₄ H₈ O)₂ Mg[Rh(CO)₂ (P(C₆ H₅)₃)₂ ]₂ has been found to be a very activehydroformylation catalyst when compared to a conventional rhodiumhydroformylation catalyst such as ((C₆ H₅)₃ P)₂ Rh(CO) Cl (see Table).

The reaction products are strictly butyraldehydes.

Reaction Conditions: 1000 psig Total pressure, CO/H₂ (50/50) mixture),60 ml benzene as solvent, 0.30-0.45 moles propylene, 0.5 mmoles catalyst(based on Rh).

    ______________________________________                                                              (%)n-    k     t.sub.1/2                                Catalyst      T° C.                                                                          C.sub.4 H.sub.8 O.sup.(a)                                                              min.sup.-1(b)                                                                       (min).sup.(c)                            ______________________________________                                        ((C.sub.6 H.sub.5).sub.3 P).sub.2 Rh(CO)Cl                                                  133     56       0.0744                                                                              9.32                                     (C.sub.4 H.sub.8 O).sub.2 Mg                                                  [Rh(CO).sub.2 (P(C.sub.6 H.sub.5)).sub.2 ].sub.2                                            95      61       0.168 4.13                                     ______________________________________                                         .sup.(a) % nC.sub.4 H.sub.8 = percent straight chain isomer, determined b     G.C. analysis.                                                                .sup.(b) k = pseudo 1st order reaction rate constant.                         .sup.(c) t.sub.1/2 = 1n 2/k.                                             

The table clearly shows that the (C₄ H₈ O)₂ Mg[Rh(CO)₂ (P(C₆ H₅)₃)₂ ]₂complex is more than twice as active as ((C₆ H₅)₃ P)₂ Rh(CO)Cl even at areaction temperature nearly 40° C. lower.

EXAMPLE 12 Hydroformylation of Hexene-1

30 ml. of hexene-1, 20 ml. of benzene, and 0.3 gm. [C₄ H₈ O]₄ Mg[Co(CO)₃PCH₃ (C₆ H₅)₂ ]₂ were placed in a rocker bomb and pressurized to 1500psi with a 1:1 ratio of H₂ :CO. The bomb was heated to 140° C. and helduntil the reaction was complete. Analysis indicated that 99% of thehexene-1 was converted to C₇ aldehydes and C₇ alcohols. 87% of thereacted product was an aldehyde.

EXAMPLE 13 Trimerization of Butadiene

0.5 gm. (C₄ H₈ O)₄ Mg[Ni(CO)C₅ H₅ ]₂ and 5 ml. of benzene were placed ina small (ca. 50 ml.) pressure reactor under a nitrogen atmosphere. Tothe catalyst was condensed 15 ml. of butadiene after passage through adrying train of CaH₂ and KOH. This mixture was warmed to 60° C. Theresulting pressure was ca. 65 psi. The mixture was allowed to stir underthese conditions for 21/2 hours, after which the pressure had dropped toless than 5 psi.

A gas chromatographic analysis of the reaction mixture showedessentially complete conversion of butadiene into the following cyclicoligomers:

    ______________________________________                                        Oligomer             % (wt.)                                                  ______________________________________                                        vinyl cyclohexene   7.6                                                       1,5-cyclooctadiene  9.9                                                       trans,trans,trans,1,5,9-cyclo-                                                dodecatriene        78.5                                                      cis,trans,trans,1,5,9-cyclo-                                                  dodecatriene        4.0                                                       ______________________________________                                    

This result is in contrast to the product distribution obtained when(Ni(CO)C₅ H₅)₂, the precursor complex in the preparation of (C₄ H₈ O)₄Mg[Ni(CO)C₅ H₅ ]₂, is employed as a catalyst. In the latter case, theprimary products are dimers (see table below).

    ______________________________________                                        Oligomer          % (weight)                                                  ______________________________________                                        vinyl cyclohexene 69                                                          1,5-cyclooctadiene                                                                              27                                                          trans,trans,trans,1,5,9-                                                      cyclododecatriene  4                                                          ______________________________________                                    

While the invention has been described in connection with specificembodiments thereof, it will be understood that it is capable of furthermodification, and this application is intended to cover any variations,uses, or adaptations of the invention following, in general, theprinciples of the invention and including such departures from thepresent disclosure as come within known or customary practice in the artto which the invention pertains and as may be applied to the essentialfeatures hereinbefore set forth, and as fall within the scope of theinvention.

What is claimed is:
 1. A catalyst composition comprising a mixtureof:(A) a compound selected from the group consisting of: (C₄ H₈ O)₄Mg[Co(CO)₃ P(C₄ H₉)₃ ]₂ and (C₄ H₈ O)₂ Mg[Rh(CO)₂ (P(C₆ H₅)₃)₂ ]₂. 2.The composition of claim 1 wherein the organo iodine compound is CH₃ I.